Purge Flow Sensor: Description and Operation
DESCRIPTIONThe EVAP Vacuum Switch, is used by the PCM to monitor EVAP canister purge solenoid operation and purge system integrity. The EVAP Vacuum Switch should be closed to ground with no vacuum present (0% EVAP Purge PWM). With EVAP Purge PWM at 25% or greater, the EVAP Vacuum Switch should open.
An incorrect EVAP Purge system flow should set a DTC P0441. A continuous purge condition with no purge commanded by the PCM should set a DTC P1441. A fault in the EVAP Vacuum Switch circuit should set a DTC P1442.